| 摘要 |
PROBLEM TO BE SOLVED: To provide an operational amplifier which can make a starting time to be a high speed and a constant current generating circuit using it. SOLUTION: The operational amplifier arranged in the constant current generating circuit is provided with a bias circuit 10, a differential stage 20, and an amplification stage 30. At a starting time of the constant current generating circuit, an output side node NGATE of the differential stage 20 can be raised more quickly from VSS to predetermined voltage level, since it is raised only specific voltage concurrently with changing timing of a starting signal EN by coupling effect because a capacitor 37 is installed between a control terminal 3c for entering the starting signal EN and the node NGATE in the operational amplifier. Consequently, the constant current generating circuit can shorten a time from starting to reach a constant current with a gain of the differential stage 20 of the operational amplifier kept small. COPYRIGHT: (C)2007,JPO&INPIT
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